The leaching of soluble salts from the plant rooting zone is a pivotal concern when irrigating cropland. Irrigation water is used to maintain crop productivity, so drought conditions need not occur to induce irrigation measures. Irrigation simply provides supplemental precipitation that may not be achieved through natural processes, i.e. rainfall.
Basically, leaching is described as passing additional water through a medium to remove unwanted materials. This is usually achieved through two types of ponding. Additional water is pumped onto the soil surface and allowed to accumulate until surface ponding occurs. There are two mechanisms that perform this duty, continuous or intermittent ponding. Intermittent ponding, applying the excess water in intervals, is more favorable for milder climates where evaporation rates are low (NATO, 1994). Continuous ponding, applying all the water at once, may not be appropriate given geographical, climatic, or user-related constraints.
Salts accumulate in the soil profile over time, therefore, leaching may serve as a form of soil “reclamation”. Normally, leaching curves are developed to determine the amount of water that may be actually required to reduce the initial soil salinity by a certain percentage (NATO, 1994). Although rainfall and the present soil already have saline concentrations, additional salts are added to the soil via irrigation water. Moisture is then extracted by the processes of evaporation and transpiration, and the salts begin to precipitate. Now, the salt balance of the soil profile changes: excessive salt concentrations are introduced without having adequate outlets. If located it the plant’s root zone, ...
... middle of paper ...
... Sustainability, Vimieo, Portugal.
Rhoades, J.D., J. Loveday (1990) Salinity in Irrigated Agriculture: Irrigation of Agricultural Crops, Agronomy #30, pp. 1107-1103.
Schwab, G.O., D.O. Fangmeier, W.J. Elliot, and R.K. Frevert (1993) Soil and Water Conservation Engineering. John Wiley and Sons, Inc. New York pp 395
United States Salinity Laboratory Staff, Richards, L.A. (ed) (1954) Diagnosis and Improvement of Saline and Alkali Soils, Agriculture handbook No. 60, United States Department of Agriculture pp 37 & 38.
Water Quality Technical Committee of the Irrigation & Drainage Division of American Society of Civil Engineers (1990) ASCE Manuals and Reports on Engineering Practice #71, Agricultural Salinity Assessment and Management, pp243-247.
Woodard, Guy O. (1969) Sprinkler Irrigation, Sprinkler Irrigation Association Editor’s Press, Maryland pp 125.
Need Writing Help?
Get feedback on grammar, clarity, concision and logic instantly.Check your paper »
- Irrigation has been around for as long as humans have been cultivating plants. Man 's first invention after he learned how to grow plants from seeds was probably a bucket. Ancient people must have been strong from having to haul buckets full of water to pour on their first plants. Pouring water on fields is still a common irrigation method today -- but other, more efficient and mechanized methods are also used. Flood (furrow) irrigation: Early man would have used this "low-tech" method of irrigating crops -- collect water in a bucket and pour it onto the fields.... [tags: Water, Irrigation, Agriculture, Hydrology]
732 words (2.1 pages)
- A. Content: This chapter emphasizes on acquiring the most important requirements, further dividing the product requirements from project requirements and makes us aware of the several requirements related problems which might occur. Generally, Requirements is a detailed description of the work need to be implemented to achieve the objectives. Behavior of the system and the environment which is suitable for the system is described by the requirements. Requirements are further generalized for the better understanding into the following types below mentioned.... [tags: Requirements analysis, Requirement]
1051 words (3 pages)
- Chemical Transport During Surface Irrigation Surface irrigation, the most prominent method used for irrigating agricultural crops, is the flowing of water across the field surface. As the water flows, it infiltrates into the soil. The amount of water applied to the field is regulated by the length of time that the water is allowed to flow. Surface irrigation can be subdivided into following four types based the amount of water flow control; wild flooding, graded boarders, level boarders and furrow irrigation.... [tags: Agriculture Farming Papers]
2032 words (5.8 pages)
- Evaluation of User Requirement Analysis in Data Warehouse Design 1.0 Introduction A data warehouse (DW) can be acknowledged as one of the most complex information system modules available and it is a system that periodically retrieves and consolidates data from the sources into a dimensional or normalized data store. It is an integrated, subject-oriented, nonvolatile and a time-variant collection of data in support of management’s decisions (Inmon, 1993). 1.1 Data Warehouse Design Process When considering the suggestions of various authors who are well known in the field, such as William Inmon and Ralph Kimball the DW design process can be divided into three main stages (Figure 1).... [tags: Requirements analysis, Requirement]
719 words (2.1 pages)
- ... As long as the water table remains deep, the salts, imported with the irrigation water, are washed down into the deeper soils with the percolation losses of irrigation water. If the water table becomes more shallow however, excess irrigation can no longer take place, otherwise the land would become flooded with stagnating water. At this point, salt leaching no longer occurs, and the salts brought in with the irrigation water accumulate in the waterlogged areas. A salinity problem becomes worse when irrigation losses from elsewhere are entering lower lying areas as groundwater flow.... [tags: farmland, production, crops, water]
821 words (2.3 pages)
- In 6000 BCE Irrigation began Mesopotamia (present day Iraq) using the water of the flooding Tigris/Euphrates rivers. The flood of water only occurred once a year From July through December. They used channels to guide the water wherever they want. These pictures will show how it used look like. In 1800 BCE They Egyptian practiced the irrigation system. It was mostly the same idea with Mesopotamia. They used water flood of Nile rive which only occurred once a year same time. Until they developed the shaduf a device that used to raise water above the Nile level.... [tags: agricultural use of water sources]
700 words (2 pages)
- In the last 50 years, irrigation systems in Bangladesh are vulnerable to drought risk for sequential years. These sequential droughts have occurred once in a period of 5 years: 1965-1966, 1972-1973, 1978-1979, 1983-1984, 1989-1990, 1994-1995, 1999-2000 and 2006-2007. Parvin and Saleh (2013) showed that average frequency of drought is about once in a 5-year return period using probability analysis of rainfall and crop water requirements in northwestern Bangladesh. Therefore, we considered a 5-year return period of a drought as a benchmark for estimating DWR for the design of agricultural water resource systems in Bangladesh.... [tags: Statistics, Normal distribution]
820 words (2.3 pages)
- Surge Irrigation Surface irrigation is not new technology, but through research and the incorporation of some inventive measures, advances in this area have provided the needed responses to make this type of irrigation increasingly appealing. Not only is water quality a major concern, but current farmers must now monitor water quality and provide adequate crop protection measures to insure a good yield. Water availability is affected by falling water tables, droughts and stressed by the increasing water demand of growing urban populations (Moody 1993).... [tags: Technology Science Agriculture Essays]
1364 words (3.9 pages)
- Heap Leaching Heap leaching is a method used most commonly for the mining of gold. Along with heap leaching comes many environmental concerns and considerations. In order to decrease these environmental concerns, there must be regulations placed on the mining of gold. Regulations can stem from control acts, enforced by the Department of Energy and other agencies similar to this, to simple regulations dealing with the equipment companies must use in their daily excavations. The heap leaching method used to extract gold uses cyanide as part of the process.... [tags: Gold Mining Miners Minerals Essays]
608 words (1.7 pages)
- Bacterial Leaching Water running out of copper mines contains dissolved copper ions that have been leached from copper minerals by bacteria. Some mines make use of bacterial leaching as a means of extracting copper from low-grade ore and tailings from conventional mining. The bacteria thiobacillus ferro-oxidants and thiobacillus thio-oxidants get the energy they need to survive by oxidising Fe2+ ions and S2- ions. The S2- ions are present in insoluble copper minerals, zinc and lead.... [tags: Papers]
643 words (1.8 pages)